Filter



March 4, 1952 G. E. BURKS ET Al. 2,587,693

l FILTER Filed April 17, 1947 2 sHEETs--SHEET 1 ATZWHNEY G. E. BURKSETAL March 4, 1952 FILTER 2 SHEETS SHEET 2 Filed April 17, 1947 lPatented Mar. 4, 1952 FILTER George E.v Burks'. Peoria, and Ronald R.Robinson, Morton, Ill., assignors to Caterpillar Tractor Co., SanLeandro, Calif., a corporation of California Application April 17, 1947,Serial No. 742,092

2. (lainis-A (Cl. 2,1 -169 )v This invention relates to filters andparticularly to filters for liquid such as lubricating Oil as it isforcibly circulated to lubricated partsy of an internal combustionengine. One type of filter in common use employs a paper-like filtermedium through which the liquid to be filtered is passed. In order toobtain a large area of filtering surface, the paper is folded back andforth in a zigzag or accordian fold and then arranged within a suitablesupporting container with its folded surfaces partially separated toadmit oil between them. The conventional container for this purpose iscylindrical and is provided with a perforated cylindrical core. Thepaper is arranged in the annular space between the core and thecontainer with its fiat surfaces between the folds disposed generallyradially of the core. In operation,` oil admitted to the containerthrough perforations in its outer wall must pass through the filterpaper in order to enter the core. Disadvantages of this constructionareV that due to the radial disposition of the folded paper its foldededges are very closely spaced at the core and too widely spaced at thecontainer Wall. This unduly limits the quantity of paper that can bearranged in a given space and also creates a condition under which thefolds of paper are too readily forced together by pressure to destroytheir emciency as a filtering medium. It is an object of this inventionto provide an improved filter and particularly an improved container fora folded filter medium wherein the capacity for filtering medium is in-.creased and the efficiency of the medium is improved. Further and morespecific objects and advantages of the invention are made apparent inthe following specification wherein one form of the invention isdisclosed for purposes of illustration by reference to the accompanyingdrawings.

In the drawings:

Fig. 1 is a horizonal sectional view through a filter unit Aembodyingthe present invention taken on the line I-I of Fig. 2;

Fig. 2 is a vertical transverse section through a filter unit containerillustrating a filter unit such as is shown in Fig. 1, partially insection and partially in end elevation; and

Fig. 3 is a fragmentary perspective view of a portion of the lter mediumused in the filter.

The filter unit shown in the drawings comprises folded paper-likefiltering medium IIJ disposed in a container made up of a perforatedouter wall II and a corrugated inner wall I2 forming a core for thecase. The outer and inner walls II and I2 may be made of sheet metal butare preferably, as illustrated, formed of inexpensive and destructiblematerial such as compressed paper or other suitable composition. Thecore I2 is slightly shorter thanthe interior of the rectangular outerwall I I so that two sections of the folded paper-like medium I0 may bejoined at their ends as indicated at I3 and the joined portions may bedisposed in the spaces between the ends of the core and the ends of theouter wall II while the folded portions will be arranged as shown inwider spaces between the sides of the core and sides of the outer wall.Y

A typical manner of supporting the filter unit is illustrated in Fig. 2wherein a chamber I4 is shown as having a removable bottom plate I5secured in place as by screws or the like I6. An inlet pipe I1communicates with theinterior of chamber I4 at one side, and an outletpipe I8 is disposed centrally of the top thereof. The filter unit issupported between a flanged top plate I9 and a similarly flanged bottomplate 20 disposed within the chamber I4. The bottom plate 20 may includea downwardly extending pilot pin 2l guided for vertical adjustment in ahollow .boss 22. A spring 23 surrounding the boss 22 and interposedbetween the removable bottom plate I5 and the unit supporting plate 20urges the plate 20 upwardly to retain the lter unit in position againstthe flanged top plate I9. The top plate I9 is perforated as at 24 andhas a fitting 25 with a restricted orifice 26 disposed for reception inthe discharge opening which receives the pipe I8. A resilient gasket 21may be employed to form a seal at this connection.

In operation, oil or other liquid to be filtered entering the chamber I4through the inlet Il passes through the perforations of the outer wall II of the filter unit as indicated by arrows in Fig. 1, then uponseepingthrough the separated layers of the filtered medium I0 is free topass through the perforations of the corrugated core I2 and to passupwardly within said core to be discharged through the opening 2li andthe dis charge pipe I8. The interior of the core may be entirelyunobstructed as illustrated in Fig. 1 or may contain additionalfiltering material in the form of cotton waste or the like as indicatedat 28 in Fig. 2.

The principal manner in which the filter unit of this inventiondistinguishes from conventional units employing folded paper-likefiltering medium is in the rectangular construction of the container Iland the inner core member I2. It

`has previously been the practice to provide a circular or tubular coresurrounded by a similar but larger container. Thus, when the foldedpaper-like medium was arranged within the annular space between the coreand the container, the capacity for folded filterA medium wasconsiderably less for a unit of a given size than with the constructionof the present invention. Because of the fact that the core of the lterunit was tubular, the several folds of the paper-like medium projectedradially with a relatively large space between their outer end and wereclosely clamped or crowded adjacent their inner ends even though theircore was corrugated to insure spacing of the inner ends. The presentinvention in providing greater capacity for filter medium reduces thenecessity for frequently changing the medium as it becomes impregnatedwith the filtrate and also effects a reduction in the unit area pressureexerted against the medium thus reducing the tendency of the individualfolds to collapse and lower the capacity of the unit.

The terms paper` and paper-like material as used throughout thespecification and claims are to be taken as referring to any at filtermedium capable of being folded but insufficiently rigid or stiff tosustain the pressures of uids being filtered without mechanical support.

We claim:

1. A filter unit adapted for insertion in a lter casing having inlet andoutlet openings, said filter unit comprising a perforate outer wallincluding opposingend and side wall portions and being open in the topand bottom, impervious top and bottom plates secured to said outer wallclosing the open top and bottom thereof, a perforate core spacedinwardly of said side wall portions and in communication with the outletof the casing through an opening formed centrally of said top plate soas to conduct ltrate away from the unit, a pair of lter sectionsdisposed in the spaces between the core and the side wall portions, eachof said sections being formed of sheet filter paper folded about axesperpendicular to said top and bottom plates to accordion-like form, theupper and lower edges of said filter sections abutting said top andbottom plates to prevent ow therearound and cause ilow from the casinginlet throug-h the perforate outer wall to pass through the filtersections and thence through the core to the outlet of the casing, thefolds of said sections nearest the core being in abutment therewith, andsaid core being vertically corrugated and formed of relatively stiffmaterial with said folds in abutment therewith individually co-operatingwith the corrugations of said core for separating and maintaining theindividual folds of the filter sections in preselected longitudinalrelationship.

2. A filter unit adapted for insertion in a lter casing having inlet andoutlet openings, said lter unit comprising a perforate outer wallincluding opposing end and side wall portions and being open at the topand bottom, impervious top and bottom plates having peripheral angessecured to said outer wall closing the open top and bottom thereof, aperforate core spaced inwardly of said side Wall portions and incommunication with the outlet of the casing through an opening formedcentrally of said top plate so as to conduct filtrate away from theunit, a pair of filter sections disposed in the spaces between the coreand the side wall portions, each of said sections being formed of sheetfilter lpapel' folded about axes perpendicular to said top and bottomplates to accordion-like form, the upper and lower edges of said filtersections abutting said top and bottom plates to prevent flow therearoundand cause flow from the casing inlet through the perforate outer wall topass through the lter sections and thence through the core to the outletof the casing, the folds of said sections nearest the core being inabutment therewith, the ends of said filter sections and core beingsecured together and said core being vertically corrugated and formed ofrelatively stiff material with said folds in abutment therewithindividually cooperating with the corrugations of said core forseparating and maintainingI the individual folds of the lter sections inpreselected longitudinal relationship.

GEORGE E. BURKS. RONALD R. ROBINSON.

REFERENCES CITED Thefollowing references are of record'in the le of thispatent:

UNITED STATES PATENTS Number Name Date 1,677,892 Herbert et al July 24,1928 2,218,800 Williams Oct. 22, 1940 2,239,868 Williams Apr. 29, 19412,372,865 Taylor Apr. 3, 1945 2,569,243 Kovacs Sept. 25, 1951 FOREIGNPATENTS Number Country Date 401,287 Great Britain Oct. 30, 1933 489,860Great Britain Aug. 4, 1948 512,972 Great Britain Sept. 29, 1939 886,736France July 12, 1943

